----"I cannot make my mark for all time...those concepts are mutually exclusive.
"Lasting effect" is a self -contradictory term. Meaning does not exist in the future, nor do I.
Nothing will have meaning, "ultimately."
Nothing will even mean tomorrow what it did today. Meaning changes with the context.

My meaningfulness is in the here and now. It is enough that I may be of value to someone today.
It is enough that I make a difference now." ~Lindsay